One of the major concerns associated with the use of printing systems having infrared dryers is the high operating temperatures of such infrared dryers, which can be on the order of 800-1000.degree. F. In particular, if the area in the vicinity of an infrared dryer is allowed to become too hot it can lead to warping or other damage to the printing system equipment. In some instances, such an excess temperature condition can be the result of simply running the infrared dryers at too high a temperature. In that case, if the operator is made aware of the problem, he can correct it by simply reducing the power supplied to the infrared lamps.
However, an excess temperature condition in the vicinity of the infrared dryers can also be an indication of a more serious problem. More specifically, if the boards, sheets or other printing substrate material become jammed in the area of the infrared dryer, the heat produced by the infrared dryer can ignite the substrate material and potentially can develop into a fire that jeopardizes not only the printing equipment, but also the safety of personnel in the area and even the plant in which the printing system is located. A build-up of dust and/or lint in the area of the infrared dryer can also create a potential fire hazard because of the high operating temperature of the dryer. These fire hazards can be compounded if the printing system continues to operate, and in particular, if the system continues to feed air to the area of the infrared dryer thereby fueling any fire, once an excess temperature condition is encountered.